Land-use and topography shape soil and groundwater salinity in Central Argentina
Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier B.V.
Abstract
tBeing one of the oldest and most serious environmental problems, soil and groundwater salinization posescritical challenges for the managing of agricultural and natural areas. Together with climate, topographyand land-use are main controls dictating salt accumulation patterns at different spatial scales. In thispaper, we quantified the response of salt accumulation to the interactive effects of topography (lowland-upland gradients) and vegetation (annual crops, tree plantations, native grasslands) across a sub-humidsedimentary landscape with shallow groundwater in the Inland Pampas of Argentina. We measured saltstocks from the surface down to the water-table through soil coring and their horizontal distributionthrough electrical-resistivity imaging in eleven fields occupied by annual crops, eucalyptus plantationsand grasslands, encompassing water-table depth gradients of 1–6 m below the surface. Land-use andtopography exerted strong influences on salinity and explained together 82% and 66% of the spatialvariability of groundwater salinity and soil salt accumulation (0–2 m of depth), respectively. As a singleexplanatory variable, land-use overwhelmed topography dictating salinity patterns. Tree plantationsstored 7–8 times more salts than croplands and grasslands throughout the unsaturated soil profile inareas with shallow water-tables (<3.5-m depth). As groundwater became shallower, its salinity and thatof the unsaturated soil above it increased, although the slope of this relationship was significantly higherin tree plantations. Soil salinity profiles and electrical-resistivity imaging showed maximum salinizationaround the water-table in tree plantations, indicating that groundwater absorption and solute exclusionby tree roots may be the dominant salinization mechanism. Our study highlights the strong influence ofland-use on salinization patterns, which can be even stronger than the more widely recognized controls ofclimate and topography, and proposes some guidelines for a better use of vegetation to manage hydrologyin salt-affected areas. A poor comprehension of this influence, as well as its underlying mechanisms, maylead to incorrect diagnosis of salinization and the implementation of ineffective management actions.
Description
item.page.type
Journal Article (peer-reviewed)
item.page.format
Keywords
SALINIZATION, SOIL WATER BALANCE, AFFORESTATION, EUCALYPTUS, GRASSLANDS, ELECTRICAL RESISTIVITY IMAGING, FOREST PLANTATIONS, ANTHROPOGENIC FACTORS, LAND USE, AGROECOLOGY
Citation
Nosetto, M.D., Acosta, A.M., Jayawickreme, D.H., Ballesteros, S.I., Jackson, R.B., & Jobbágy, E.G. (2013). Land-use and topography shape soil and groundwater salinity in central Argentina. Agricultural Water Management, 129, 120-129. http://dx.doi.org/10.1016/j.agwat.2013.07.017